U.S. patent number 4,916,172 [Application Number 07/248,086] was granted by the patent office on 1990-04-10 for reaction curable composition and artificial marble.
This patent grant is currently assigned to Asahi Glass Company, Ltd.. Invention is credited to Takao Hayashi, Kazuhiko Kameda.
United States Patent |
4,916,172 |
Hayashi , et al. |
April 10, 1990 |
Reaction curable composition and artificial marble
Abstract
A reaction curable composition comprising a curable component, a
polymerization initiator for curing the curable component and from
30 to 90% by weight, based on the total composition, of inorganic
fillers, wherein the curable component is a combination of a
polyfunctional allylcarbonate monomer or its precondensate, an
unsaturated polyester and a reactive diluent, or a combination of a
partially cured product of at least two of such three components
and the rest of such three components, if any.
Inventors: |
Hayashi; Takao (Zushi,
JP), Kameda; Kazuhiko (Yokohama, JP) |
Assignee: |
Asahi Glass Company, Ltd.
(Tokyo, JP)
|
Family
ID: |
26453520 |
Appl.
No.: |
07/248,086 |
Filed: |
September 23, 1988 |
Foreign Application Priority Data
|
|
|
|
|
Sep 25, 1987 [JP] |
|
|
62-238981 |
May 13, 1988 [JP] |
|
|
63-114862 |
|
Current U.S.
Class: |
523/171; 523/500;
523/506; 523/514; 523/521 |
Current CPC
Class: |
C04B
24/003 (20130101); C04B 26/18 (20130101); C08F
299/0478 (20130101); C04B 26/18 (20130101); C04B
14/303 (20130101); C04B 24/003 (20130101); C04B
26/18 (20130101); C04B 14/303 (20130101); C04B
24/42 (20130101); C04B 2111/545 (20130101) |
Current International
Class: |
C04B
24/00 (20060101); C04B 26/00 (20060101); C04B
26/18 (20060101); C08F 299/04 (20060101); C08F
299/00 (20060101); C08K 003/36 (); C08K 003/34 ();
C08K 003/26 (); C08K 003/22 () |
Field of
Search: |
;523/171,500,506,514,521
;525/37,39,48 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Jacobs; Lewis T.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt
Claims
We claim:
1. A reaction curable composition comprising a curable component, a
polymerization initiator for curing the curable component and an
amount of from 30 to 90% by weight, based on the total composition,
to effect the appearance of marble upon curing, of an inorganic
filler selected from the group consisting of aluminum hydroxide,
magnesium hydroxide, silica, calcium carbonate, calcium silicate,
kaolin, clay or talc, wherein the curable component is a
combination of a polyfunctional allylcarbonate or its
precondensate, an unsaturated polyester and a reactive diluent, or
a combination of a partially cured product of at least two of such
three components and the uncured remainder thereof if there be
any.
2. The reaction curable composition according to claim 1, wherein,
the curable component is a combination comprising 100 parts by
weight of the polyfunctional allylcarbonate monomer or its
precondensate, from 10 to 490 parts by weight of the unsaturated
polyester and from 10 to 490 parts by weight of the reactive
diluent, and the total of the unsaturated polyester and the
reactive diluent is from 30 to 500 parts by weight, or a
combination comprising a partially cured product of such three
components in the above proportions.
3. The reaction curable composition according to claim 1, wherein
the polyfunctional allylcarbonate monomer is diethylene glycol
bis(allylcarbonate).
4. The reaction curable composition according to claim 1, wherein
the reactive diluent is a monofunctional or polyfunctional
methacrylate.
5. The reaction curable composition according to claim 1, wherein
the inorganic filler is aluminum hydroxide.
6. The reaction curable composition according to claim 1, which
contains from 0.1 to 5% by weight of at least one compound selected
from the group consisting of organic phosphoric acid esters and
silane coupling agents, as a part of the reactive diluent or as an
additional component.
7. The reaction curable composition according to claim 6, wherein
the organic phosphoric acid esters are phosphoric acid esters of
methacrylic acid represented by the formula: ##STR5## wherein n is
an integer of 1 or 2.
8. An artificial marble obtained by molding and curing the reaction
curable composition of claim 1.
9. An artificial marble obtained by molding and curing the reaction
curable composition of claim 2.
10. An artificial marble obtained by molding and curing the
reaction curable composition of claim 6.
Description
The present invention relates to a reaction curable composition and
an artificial marble obtained by molding and curing the
composition. More particularly, the present invention relates to a
reaction curable composition for the production of an artificial
marble having high mechanical strength and excellent weather
resistance and stain resistance and having an excellent
processability, and an artificial marble obtained by molding and
curing such a composition.
Heretofore, an artificial marble prepared by molding and curing a
resin composition is practically employed for various applications
including sanitary wares such as toilet tables, bath tubs or
kitchen counters, and building interior or exterior materials. To
obtain such an artificial marble in the form of a molded resin
product, it is common to employ a casting method wherein a
composition prepared by blending and mixing e.g. inorganic fillers
or fibrous reinforcing material to a resin as matrix constituting
the artificial marble is filled in a mold, followed by curing.
Otherwise, a compression molding method is employed by using SMC
(sheet-molding compound) which is prepared by blending inorganic
fillers, a thickener and other additives to a resin, impregnating
the blend to e.g. glass fibers and enclosing the impregnated glass
fibers with a film to form a sheet, or BMC (bulk-molding compound)
which is prepared in the same manner but in a bulk form.
The matrix resin used in such molding methods, is usually an
unsaturated polyester resin. However, an artificial marble made of
such a resin is more or less inferior in its appearance. For
example, an artificial marble prepared by using an unsaturated
polyester resin as matrix, has little transparency and thus has a
drawback that an appearance due to transparency specific to marble
can not be obtained. It has been proposed to overcome such a
drawback (Japanese Unexamined Patent Publications No. 66462/1984
and No. 101552/1986).
On the other hand, reflecting an increasing demand for high
quality, the artificial marble is required to have an appearance
which gives a gorgeous impression with the internal patterns of the
molded product to be seen through due to the transparency, to have
mechanical strength such as flexural strength and impact strength
and to have improved surface hardness or the heat resistant
properties. Accordingly, an attention has been drawn to a
methacrylate resin having good transparency and mechanical strength
as such a matrix resin.
A number of proposals have been made with respect to an artificial
marble or a composition for an artificial marble wherein a
methacrylate resin is used as matrix. As basic proposals, a product
obtained by curing a mixture of a methyl methacrylate polymer with
an alumina hydrate (Japanese Examined Patent Publication No.
22586/1975, U.S. Pat. No. 3,847,865) and a granite product composed
of opaque or translucent particles of predetermined particle sizes
wherein a methyl methacrylate polymer and alumina trihydrate
particles are used as matrix (Japanese Unexamined Patent
Publication No. 72707/1977, U.S. Pat. No. 4,085,246), are known.
Further, as proposals having a feature in the combination with a
filler, it has been proposed, for example, to incorporate aluminum
hydroxide (Japanese Examined Patent Publication Nos. 22586/1975 and
43222/1980), to incorporate a combination of aluminum hydroxide
with either one of magnesium hydroxide, magnesium carbonate and
aluminum oxide (Japanese Unexamined Patent Publication No.
104621/1978), to incorporate silica (Japanese Unexamined Patent
Publication No. 4611/1981), and to incorporate calcium silicate
(Japanese Unexamined Patent Publication No. 33308/1984). Further, a
methacrylate resin composition containing a filler and having its
fluidity during the molding improved, is also disclosed (Japanese
Unexamined Patent publication No. 245609/1985).
As described in the foregoing, the matrix resin is being changed
from an unsaturated polyester resin to a methacrylate resin.
Further, an artificial stone molded product has also been proposed
which is composed of a polymer of a composition comprising as
matrix a polyfunctional allylcarbonate resin, preferably diethylene
glycol bis(allylcarbonate) polymer, known as a resin having
excellent transparency as well as high strength and abrasion
resistance and fine powder of silica or alumina hydrate (Japanese
Unexamined Patent Publication No. 111953/1986).
As described in the foregoing, the matrix resin for an artificial
marble is desired to be a resin having excellent transparency so
that the molded artificial marble will have an appearance which
gives a gorgeous impression, and for this purpose, a methacrylate
resin is generally regarded as a suitable resin. However, there is
a problem that the methacrylate resin and a filler are usually
substantially different in various properties, and the resin and
the filler have poor affinity or adhesion particularly due to the
difference in their interfacial properties. Further, when the
filler is incorporated, the viscosity increases by the
incorporation, whereby it becomes extremely difficult to uniformly
disperse the filler. Accordingly, there is a problem that it is
difficult to improve the properties of the artificial marble or to
reduce the cost by increasing the amount of the filler.
Consequently, the artificial marble thereby obtained has a drawback
that the mechanical strength such as the flexural strength or
impact strength is practically inadequate. In order to overcome
such drawback, it has been proposed that the filler is subjected to
surface treatment, for example, with a silane coupling agent, and
such a surface-treated filler is incorporated to a resin. However,
no adequate effect has yet been obtained. Besides, an increase of
the manufacturing cost is thereby unavoidable. Furthermore, no
adequate stain resistance or chemical resistance will be obtained
by such a means for improvement.
Similar problems exist in the case where a polyfunctional
allylcarbonate having excellent transparency is used as the matrix
resin. Namely, diethylene glycol bis(allylcarbonate) has poor
affinity and adhesion to an inorganic filler. Accordingly, the
inorganic filler is not adequately dispersed in the matrix resin,
whereby it is extremely difficult to incorporate a substantial
amount of the filler. Even when the filler is incorporated in a
small amount, it is likely that the filler is non-uniformly present
in the molded product as an artificial marble, whereby a gorgeous
appearance is hardly obtainable. Besides, the mechanical strength
tends to be low. For example, when being cut or drilled for
processing, the molded product is likely to undergo breakage to
form a defective product.
With a composition containing diethylene glycol bis(allylcarbonate)
as the matrix resin, it is necessary to heat it to gradually raise
the temperature to obtain a molded product, whereby an extremely
long time is required.
In view of the above problems, the present inventors have conducted
various studies and researches to obtain an artificial marble
having excellent properties by incorporating inorganic fillers to a
copolymer in which various polymerizable monomers capable of
providing a transparent resin are used in combination, so that the
drawback of a conventional artificial marble composed solely of a
single resin matrix is complemented and the properties are improved
as the synergistic effect.
Accordingly, it is an object of the present invention to provide a
reaction curable composition useful for the preparation of an
artificial marble in which inorganic fillers are uniformly
dispersed in a resin matrix and have an improved adhesion and which
has thus excellent in the mechanical strength, the surface
smoothness, the gloss, the stain resistance and the chemical
resistance and has an appearance with a gorgeous impression and
which has good processability, and to provide an artificial marble
obtained by molding and curing such a composition.
The present invention provides a reaction curable composition
comprising a curable component, a polymerization initiator for
curing the curable component and from 30 to 90% by weight, based on
the total composition, of inorganic fillers, wherein the curable
component is a combination of a polyfunctional allylcarbonate
monomer or its precondensate, an unsaturated polyester and a
reactive diluent, or a combination of a partially cured product of
at least two of such three components and the rest of such three
components, if any.
Now, the present invention will be described in detail with
reference to the preferred embodiments.
The polyfunctional allylcarbonate monomer in the present invention
is a monomer-having at least two allylcarbonate groups ##STR1## and
a polyol residue. The polyol residue is derived from an aliphatic
or alicyclic polyol having from 2 to 4 hydroxyl groups at least two
hydroxyl groups. As such a polyol, ethylene glycol, diethylene
glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol,
1,6-hexanediol, glycerol or trimethylolpropane may be mentioned. A
preferred polyol is an aliphatic diol, and particularly preferred
is diethylene glycol. The most preferred polyfunctional
allylcarbonate monomer is diethylene glycol bis(allylcarbonate)
represented by the formula: ##STR2## This monomer is polymerized in
the presence of a polymerization initiator to form a cured product
having excellent transparency and high mechanical strength and
abrasion resistance. Thus, this is presently used as a main
material for plastic lenses. Further, it is possible to use a
prepolymer obtained by preliminary partial polymerization of this
monomer. This prepolymer is preferably the one obtained by the
polymerization reaction of the monomer in the presence of a
polymerization initiator to have a polymerization degree of from 1
to 100 poise (25.degree. C. as measured by B model viscometer).
Further, it is possible to use a mixture of this monomer and the
prepolymer.
The unsaturated polyester in the present invention is a compound
called also as alkyd resin which has at least several unsaturated
groups. Preferably it is a polyester oligomer having an unsaturated
polybasic acid residue, a saturated polybasic acid residue and a
saturated polyol residue. Such polybasic acid residue and saturated
polyol residue are preferably divalent, but may contain a small
amount of a tri- or higher divalent residue. As the unsaturated
polybasic acid residue, a maleic acid residue or a fumaric acid
residue is preferred. As the saturated polybasic acid residue, a
residue of e.g. succinic acid, adipic acid, sebacic acid,
orthophthalic acid, isophthalic acid or terephthalic acid is
preferred. The polyol is preferably a diol such as ethylene glycol,
diethylene glycol, propylene glycol, dipropylene glycol, 1,4-, 1,3-
or 2,3-butanediol, neopentyl glycol or 1,6-hexanediol. Further,
such a diol may be used in combination with a small amount of a
tri- or higher valent polyol such as glycerol or trimethylol
propane. By incorporating an unsaturated polyester to the
above-mentioned polyfunctional allylcarbonate monomer or its
precondensate, the curing rate of the polyfunctional allylcarbonate
polymer or its precondensate can remarkably be accelerated.
The reactive diluent in the present invention is a monomer having a
viscosity lower than the unsaturated polyester and containing at
least one .alpha.,.beta.-unsaturated group. For example, it may be
a liquid olefin such as monofunctional or polyfunctional
methacrylate or acrylate, or styrene. Preferably, a monofunctional
or polyfunctional methacrylate such as an alkyl methacrylate or a
polymethacrylate of a polyol. Specifically, it includes methyl
methacrylate, ethyl methacrylate and 2-ethylhexyl methacrylate.
These diluents may be used alone or in combination. Among them,
methyl methacrylate is most preferred, since it is readily
available. Such a reactive diluent may be employed in the form of a
preliminarily partially polymerized prepolymer, but is preferably
used in the form of a monomer as a reactive diluent for controlling
the viscosity of the reaction curable composition.
The proportions of the polyfunctional allylcarbonate monomer or its
precondensate, the unsaturated polyester and the reactive diluent
in the curable component of the present invention are such that the
unsaturated polyester is from 10 to 490 parts by weight and the
reactive diluent is from 10 to 490 parts by weight, relative to 100
parts by weight of the polyfunctional allylcarbonate monomer or its
precondensate, and the total of the unsaturated polyester and the
reactive diluent is from 300 to 500 parts by weight. If the
proportions depart substantially from these ranges, the artificial
marble obtained by molding and curing the reaction curable
composition tends to be poor in the appearance and in the
mechanical properties.
The polyfunctional allylcarbonate monomer and the reactive diluent
constituting the curable component of the reaction curable
composition may be preliminarily polymerized partially. In such a
case, the proportions of the respective components are the same as
specified above.
In the reaction curable composition of the present invention, the
viscosity is increased by the incorporation of the inorganic filler
to the curable component. If the viscosity is too high, the casting
of the composition into a mold will be difficult, and defoaming
tends to be incomplete, which is likely to bring about a defective
appearance or a deterioration of the molding product. Therefore, it
is important to adjust the viscosity to a proper level. For this
purpose, the reactive diluent is used as an essential component,
and the incorporation in a liquid state is particularly preferred.
Further, it is preferred to incorporate at least one compound
selected from the group consisting of organic phosphoric acid
esters and silane coupling agents, as a part of the reactive
diluent or as an additional component of the reaction curable
composition.
By the incorporation of a small amount of a phosphoric acid ester
of methacrylic acid represented by the formula: ##STR3## wherein n
is an integer of 1 or 2, as the organic phosphoric acid ester, the
mechanical properties and particularly the processability of the
artificial marble obtained by molding and curing the reaction
curable composition will be remarkably improved. This ester is used
usually in an amount of from 0.1 to 5% by weight, preferably from
0.5 to 3% by weight. Even if the amount exceeds 5% by weight, no
additional effect will be obtained. If the amount is less than 0.1%
by weight, no adequate effect will be obtained. Even when this
compound is not incorporated, the artificial marble will have
practically adequate properties.
As the organic phosphoric acid ester, an alkyl phosphate of the
formula: ##STR4## wherein R is an alkyl group having from 8 to 12
carbon atoms, and m is an integer of 1 or 2, may be used as a
reactive diluent or as an additional component to adjust the
viscosity of the reaction curable composition. This ester may be
incorporated in an amount of from 0.1 to 5% by weight, preferably
from 0.5 to 1% by weight, and by the combination with the compound
of the above formula I, the properties of the artificial marble may
further be improved.
Further, in order to improve the dispersibility of the organic
filler or its adhesion with the resin, it is effective to
incorporate, for example, a silane coupling agent or an inorganic
filler treated with a silane coupling agent.
In order to mold and cure the reaction curable composition to
obtain an artificial marble, the reaction curable composition
contains a polymerization initiator. Specific examples of such a
polymerization initiator include benzoyl peroxide (BPO), cumene
hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide,
diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate and
di(2-ethylhexyl)peroxycarbonate. Particularly preferred is benzoyl
peroxide or diisopropylperoxydicarbonate. Such a polymerization
initiator is incorporated in an amount of from 0.5 to 10 parts by
weight, preferably from 1 to 7 parts by weight, relative to 100
parts by weight of the curable component.
The reaction curable composition of the present invention contains
an inorganic filler in addition to the above-mentioned curable
component. Such an inorganic filler may be aluminum hydroxide,
magnesium hydroxide, silica, calcium carbonate, calcium silicate,
kaolin, clay or talc which is commonly used in the conventional
artificial marble. Among such inorganic fillers, aluminum hydroxide
is preferred, since the artificial marble thereby obtained will
have excellent chemical resistance, particularly against acidic
solutions. Such inorganic fillers are preferably in a particle
form, and the particle size of the fillers is preferably at a level
of an average particle size of from 0.6 to 50 .mu.m. The smaller
the particle size, the higher the whiteness of the artificial
marble, but the light transmitting properties tend to decrease.
Further, the smaller the particle size, the higher the viscosity
with the same amount of incorporation, and the operation efficiency
tends to be low. On the contrary, the larger the particle size, the
lower the viscosity, and the amount of incorporation can be
increased, but the dispersibility tends to be poor, and the
precipitation of the fillers tends to take place, thus leading to a
deterioration of the physical strength of the artificial marble.
Therefore, the particle size is preferably within a range of from 3
to 10 .mu.m. And the amount of incorporation is from 30 to 90% by
weight, based on the entire curable component. If the amount is
less than 30% by weight, it becomes difficult to obtain a color
tone as an artificial marble, and if it exceeds 90% by weight,
uniform dispersion tends to be difficult.
To the reaction curable composition of the present invention, it is
of course possible to incorporate fibrous materials such as glass
fibers or other additives for the purpose of improving the
moldability or the properties of the artificial marble.
The polymerization may be conducted at a temperature of from
80.degree. to 120.degree. C. for from 2 to 4 hours. Preferably, the
temperature is stepwise raised from a low temperature. The
polymerization molding time can be made remarkably short as
compared with the polymerization molding condition in the case
where diethylene glycol bis(allylcarbonate) was used alone.
A conventional casting mold may be used as the mold to obtain the
artifical marble. Further, other molds useful for continuous
molding may be employed. There is no particular restriction as to
the type of the mold.
Now, the present invention will be described in further detail with
reference to Examples. However, it should be understood that the
present invention is by no means restricted to such specific
Examples.
EXAMPLES 1 to 3
Diethylene glycol bis(allylcarbonate) ("CR-39", manufactured by PPG
Co.), an unsaturated polyester ("Upica 8639", tradename,
manufactured by Japan Upica Co., Ltd.) and methyl methacrylate, as
monomers, and aluminum hydroxide ("Hydilight H-320", average
particle size: 3 .mu.m, manufactured by Showa Denko K.K.) as an
inorganic filler were blended in the proportions as identified in
Table 1. Further, benzoyl peroxide was added as a polymerization
initiator in the amount as identified in Table 1, and a silane
coupling agent ("A-174", manufactured by Nippon Unica Co.) was
added in an amount of 1% by weight relative to the inorganic
filler. The mixture was uniformly mixed and defoamed to obtain a
composition. The viscosities of this composition was measured. The
results are shown in Table 1.
Then, this composition was cast in a mold assembled by reinforced
glass sheets. After confirming that no remaining foams existed, the
mold was put in an air oven at a temperature of 80.degree. C., and
it was then heated to a temperature of 100.degree. C. over a period
of 2 hours and further to 120.degree. C. over a period of 1 hour
and maintained at 120.degree. C. for 30 minutes for polymerization
molding.
The mold was taken out from the air oven, cooled and then
disassembled to obtain an artificial marble of 50 cm.times.50
cm.times.12 mm in thickness as the molded product.
The following properties were measured with respect to the
artificial marble thus obtained. The results are shown in Table 1.
As the mechanical strength, the flexural strength and the flexural
modulus were measured in accordance with JIS K-7203, the Izod
impact strength (notched) was measured in accordance with JIS
K-7110, the Barcole hardness (GYZ J934-1) was measured, and, the
appearance of the surface was visually inspected.
COMPARATIVE EXAMPLES 1 to 3
Diethylene glycol bis(allylcarbonate) and aluminum hydroxide;
diethylene glycol bis(allylcarbonate), an unsaturated polyester
("Upica 8639") and aluminum hydroxide; and diethylene glycol
bis(allylcarbonate), methyl methacrylate and aluminum hydroxide,
were mixed, respectively, in the proportions as identified in Table
1, and treated in the same manner as in Examples 1 to 3 to obtain
paste compositions, which were further polymerized and cured for
molding to obtain artificial marbles as molded products.
The properties of the artificial marbles thus obtained were
measured. The results are shown in Table 1.
EXAMPLE 4
A polymerization initiator was added to diethylene glycol
bis(allylcarbonate), and the mixture was heated at 80.degree. C.
for 2 hours to obtain a prepolymer. This prepolymer was mixed with
other components in the proportions as identified in Table 1 to
obtain a composition, which was put in an air oven in the same
manner as in Examples 1 to 3, heated to 80.degree. C. over a period
of one hour and further to 120.degree. C. over a period of one
hour, and then maintained at 120.degree. C. for 30 minutes for
polymerization molding to obtain an artificial marble as a molded
product.
The properties of the artificial marble thus obtained were
measured. The results are shown in Table 1.
TABLE 1
__________________________________________________________________________
Example Comparative Example 1 2 3 4 1 2 3
__________________________________________________________________________
Composition Diethylene glycol (parts by bis(allylcarbonate) 140 210
100 100 350 210 210 weight) Unsaturated polyester 140 70 200 50 --
140 -- Methyl methacrylate 70 70 50 200 -- -- 140 Aluminum
hydroxide 650 650 650 650 650 650 650 Silane coupling agent 6.5 6.5
6.5 6.5 6.5 6.5 6.5 Benzoyl peroxide 10.5 10.5 10.5 10.5 10.5 10.5
10.5 Viscosity (CPS.25.degree. C.) 5500 3800 12000 1800 2300 10000
2200
__________________________________________________________________________
Example Comparative Example 1 2 3 4 1 2 3
__________________________________________________________________________
Properties Mechanical Flexural strength 5.3 4.3 4.2 3.8 2.0 3.5 2.7
properties (kgf/mm.sup.2) Flexural modulus 780 500 450 480 320 480
400 (kgf/mm.sup.2) Izod impact 1.7 1.5 1.4 1.4 1.1 1.4 1.2 strength
(kgf/mm.sup.2) (notched) Barcole hardness 61 52 50 47 22 45 30
Appearance Good Good Good Good *1 *2 *3
__________________________________________________________________________
Notes: *1: Surface susceptible to scratching. Inadequate curing.
*2: Numerous foams remain. *3: Nonuniform dispersion of aluminum
hydroxide. Inadequate curing.
EXAMPLES 5 to 7
Paste compositions were prepared in the same manner as in Examples
1, 2 and 4 except that phosphoric acid ester of 2-hydroxyethyl
metacrylate ("JPA 514", manufactured by Johoku Kagaku Kogyo K.K.)
was used instead of the silane coupling agent, an alkyl phosphate
("Gafac RS-710", tradename, manufactured by Toho Kagaku K.K.) was
used as a viscosity-reducing agent, and other additives as
identified in Table 2 were used.
Then, by using these paste compositions, artificial marbles were
prepared by the polymerization molding in the same manner as in
Examples 1, 2 and 4.
The properties of the artificial marbles thus obtained are shown in
Table 2. As additional properties, the processability was examined
by drilling and cutting, whereby the production of defective
products was ascertained. The results are shown in Table 2.
TABLE 2 ______________________________________ Example 5 6 7
______________________________________ Composition Diethylene
glycol 140 210 100 (parts by bis(allylcarbonate) weight)
Unsaturated polyester 140 70 50 Methyl methacrylate 70 70 200
Aluminum hydroxide 650 650 650 Phosphoric acid ester 6.5 6.5 6.5 of
2-hydroxyethyl methacrylate Alkyl phosphate 3.2 3.2 3.2 Benzoyl
peroxide 10.5 10.5 10.5 Tinuvin P 3.5 3.5 3.5 (ultraviolet
absorber) "Byk A-515" 5 5 5 (defoaming agent)* Viscosity
(CPS.25.degree. C.) 5000 1800 700
______________________________________ Example 5 6 7
______________________________________ Properties Mechanical
Flexural 6.0 7.7 6.0 properties strength (kgf/mm.sup.2) Flexural
800 830 800 modulus (kgf/mm.sup.2) Izod impact strength
(kgf/mm.sup.2) Notched 1.5 1.8 1.3 Not notched 7.0 10.0 6.5 Tensile
4.0 4.3 4.0 strength (kg/mm.sup.2) Barcole hardness 65 65 65
Appearance Good Good Good Processability Good Good Good
______________________________________ *Manufactured by Byk Chemie
Co.
EXAMPLE 8
With respect to the artificial marble obtained in Example 1, the
stain resistance was measured in accordance with JIS K-6902.
Further, with respect to the chemical resistance, the surface
change was examined in accordance with JIS K-7114 by using 20%
hydrochloric acid, 10% sulfuric acid, 10% sodium hydroxide,
halogenated hydrocarbons, reagent acetone, benzene and toluene.
Further, the flame retardancy was measured in accordance with JIS
A-1321.
The above results are shown in Table 3.
COMPARATIVE EXAMPLE 4
With respect to the artificial marble obtained in Comparative
Example 2, the stain resistance and the chemical resistance were
measured in the same manner as in Example 8. The results are shown
in Table 3. (The tests on the products obtained in Comparative
Examples 1 and 3 were omitted since the curing was inadequate with
such products.)
TABLE 3 ______________________________________ Compara- tive
Example 8 Example 4 ______________________________________ Stain
Tea A B resistance Coffee A B Milk A B 1% Iodine alcohol B C
solution Vinegar A B 10% Citric acid A B aqueous solution Gasoline
A B Acetone A B (industrial grade) Olive oil A B 10% Ammonium A B
Red crayon A C Black shoe paste A B Red pigment for food A B No.
102, 0.01% aqueous solution Blue black ink B C 2% Mercurochlorme A
C aqueous solution 5% Carbolic acid A B aqueous solution Saturated
acid A B sodium sulfite aqueous solution Soy source A C Chemical
20% Hydrochloric A B resistance acid 10% Sulfuric acid A B 10%
Sodium A B hydroxide Chloroform B C Carbon tetrachloride A B
1,2-Dichloroethane B C 1,1,1-Trichloro- B C ethane Chlorobenzene A
B Reagent acetone A B Reagent benzene A B Reagent toluene A B
Reagent xylene A B Flame Temperature time 33*.sup.2 -- retardancy
surface area Td .theta. (.degree.C. min) Fuming coefficient
10*.sup.3 -- CA (-) Flame remaining 2*.sup.4 -- time (sec)
______________________________________ *Evaluation A: No change B:
Slight change C: Strong change *.sup.2 Standard < 350 *.sup.3
Standard < 120 *.sup.4 Standard < 30
The artificial marble obtained by molding and curing the reaction
curable composition of the present invention has features that the
dispersion of the inorganic filler in the matrix resin is excellent
and accordingly has a high level of whiteness, a light
transmittance and an appearance similar to natural marble. As
compared with conventional artificial marbles, it is excellent not
only in the mechanical strength but also in the stain resistance,
chemical resistance and processability, and thus suitable for use
in a wide range of applications. Further, the polymerization of the
reaction curable composition of the present invention to prepare an
artificial marble can be remarkably shortened as compared with e.g.
the polymerization of a composition containing diethylene glycol
bis(allylcarbonate) as the sole curable component.
* * * * *